检索结果-南通市图书馆

Photoluminescence upgradation of La_(2)MgTiO_(6):2%Dy^(3+) perovskite with monovalent(Li^(+)),divalent(Ba^(2+),Sr^(2+)) and trivalent(Bi^(3+),Sm^(3+))cation sensitization

在线全文

学校读者我要写书评

暂无评论

Journal of rare Earths 2025年第1期43卷 47-56,I0002页

作者： v.P.veena k.Arun C.k.Shilpa S.v.Jasira k.M.Nissamudeen School of Pure and Applied Physics Kannur UniversityPayyanur CampusEdatKannurKrala67 India Department of Nanoscience and Nanotechnology Kannur UniversityPayyanur CampusEdatkannurKerala670327India

Nano phosphors of 2%Dy^(3+)(wt%)doped La_(2)MgTiO_(6) and monovalent/divalent/trivalent co-doped La_(1.98)Dy_(0.02)MgTiO_(6):x%A^(y+)(A^(y+):Li+,Ba^(2+),Sr^(2+),Bi^(3+),and Sm^(3+);0≤x≤2 wt%)were synthesized by combustion *** the XrD data,it is deduced that an increase in the valency of co-dopant increases the crystallinity of the double perovskite orthorhombic nanocrystal *** an increase in co-dopant size,an elevation in optical bandgap is visible with the highest bandgap of 3.835 ev for Bi^(3+).The photo-absorption is monotonically broadened for Sr^(2+),Sm^(3+),and Li+around 200-450 ***351 nm,Dy^(3+)triggered lattice shows major characteristic emission peaks at 480 nm(^(4)F_(9/2)→^(6)H_(15/2)),574 nm(^(4)F_(9/2)→^(6)H_(13/2)),and 670 nm(^(4)F_(9/2)→^(6)H_(11/2)).leading to near white light emission with CIE coordinates(0.341,0.376).Upon co-doping,the PL intensity is significantly increased with maximum emission for trivalent Sm^(3+),followed by divalent Sr^(2+)and monovalent Li+*** increasing excitation wavelength,Sr^(2+)shows a dominated output and it is found that divalent Sr^(2+)is a potential codopant that could enhance luminescence intensity up to 6 times with a Sr^(2+)→Dy^(3+)energy transfer efficiency of 86%.It is specified that the CIE coordinates of Li+co-doped samples show ideal white emission with color coordinates(0.333,0.336).The concluding outcomes signify the noblest rare earth Sm^(3+)co-doping and thus Sm^(3+)→Dy^(3+)energy transfer mechanism is discussed in detail.

关键词： Photoluminescence Perovskite WLED Co-doping rareearths

Cardiovascular involvement in multisystem inflammatory syndrome in children and midterm follow-up from a pediatric tertiary center in India

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Pediatrics 2025年第1期14卷 127-138页

作者： Poovazhagi varadarajan ritchie Sharon Solomon Seenivasan Subramani ramesh subramanian Gomathy Srividya Elilarasi raghunathan Department of Pediatric Intensive Care Institute of Child Health and Hospital for ChildrenMadras Medical CollegeChennai 600003Tamil NāduIndia Department of Pediatric Cardiology Institute of Child Health and Hospital for ChildrenMadras Medical CollegeChennai 600003Tamil NāduIndia Department of Pediatrics Institute of Child Health and Hospital for ChildrenMadras Medical CollegeChennai 600003Tamil NāduIndia

BACkGrOUND In multisystem inflammatory syndrome in children(MIS-C)with coronavirus disease 2019,there was paucity of data from low-income and middle-income countries on cardiovascular involvement and its longitudinal *** planned to estimate the pattern of cardiovascular involvement among children with MIS-C and its mid-term *** To determine association between cardiovascular abnormalities and clinical and laboratory *** study the time-line for resolution of various *** In this prospective study done in a tertiary care hospital,270 were recruited from June 2020 to January *** demographic data and clinical presentation were *** parameters and echocardiography were done at ***-up was done at 2 weeks,3 months,6 months and 1 year after *** statistics were used for parametric and non-parametric *** factors were identified by multivariate regression *** The 211(78.2%)had cardiac involvement and 102 needed intensive care unit(ICU)*** abnormalities observed were shock 123(45.6%),coronary dilatation 28(10.4%),coronary aneurysm 77(28.5%),left ventricular(Lv)dysfunction 78(29.3%),mitral regurgitation(Mr)77(28.5%)and pericardial effusion 98(36.3%).Coronary artery aneurysm/dilatation during follow-up at 2 weeks and 1 year were 25.7%and 0.9%*** regression analysis revealed breathlessness[odds ratio(Or)=3.91,95%CI:1.25-12.21,P=0.019]and hi-flow nasal cannula(HFNC)support(Or=8.5,95%CI:1.06-68.38,P=0.044)as predictors of cardiovascular *** mean age(Or=1.16,95%CI:1.02-1.32,P=0.026),breathlessness(Or=4.99,95%CI:2.05-12.20,Pr=4.45,95%CI:0.41-2.52,P=0.016),Mr(Or=3.61,95%CI:1.53-8.53,P=0.004)and invasive ventilation(Or=4.01,95%CI:1.28-12.58,P=0.017)were predictive of Lv *** sensorium(Or=4.96,95%CI:2.23-11.02,Pr=6.61,95%CI:1.46-29.92,P=0.014),HFNC(Or=7.03,95%CI:2.0

关键词： Multisystem inflammatory syndrome in children Cardiovascular Midterm follow-up Coronary artery aneurysm Shock Left ventricular dysfunction

Characteristics of Energy Fluxes and Cold Frontal Effects on Energy Exchange over a Boreal Lake

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2025年第2期42卷 357-372页

作者： Lujun XU Huizhi LIU Ivan MAMMArELLA Aki vÄHÄ Joonatan ALA-kÖNNI Xuefei LI Qun DU Yang LIU Timo vESALA State key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100864China Department of Atmospheric Sciences Yunnan UniversityKunming 650091China Institute for Atmospheric and Earth System research/Physics Faculty of ScienceUniversity of HelsinkiHelsinki 00014Finland

Understanding the characteristics and variations of heat exchange and evaporation of lakes is important for regional water resource management and sustainable *** on eddy covariance measurements over Lake vanajavesi in southern Finland,characteristics of energy fluxes and cold frontal effects on energy exchange were *** lake acted as a heat sink in spring and summer and a heat source in *** latent heat flux reached its minimum value in the morning and peaked in the *** diurnal variation of sensible heat flux was opposite to that of latent heat *** factors for the sensible heat flux were mainly the lake-air temperature difference and the product of lake-air temperature difference and wind *** latent heat flux was mainly affected by the vapor pressure deficit and the product of vapor pressure deficit and wind *** annual mean values of bulk transfer coefficients for momentum,heat,and water vapor were 1.98×10^(-3),1.62×10^(-3),and 1.31×10^(-3),*** transfer coefficients for heat and water vapor were not equal,indicating that the parameterization of energy exchange in numerical models,where the assumption that the heat coefficient equals the water vapor coefficient needs *** the ice-free season,cold fronts resulted in 28 sensible heat pulses and 17 latent heat pulses,contributing to 50.59%and 34.89%of sensible and latent heat exchange in Lake *** results indicate that cold fronts significantly impact the surface energy budget and evaporation over lakes.

关键词： sensible heat flux latent heat flux roughness length bulk transfer coefficient cold front

Design and Analysis of Novel Three-Phase PFC for IM Drives

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Intelligent Automation & Soft Computing 2023年第1期35卷 231-241页

作者： v.kavitha k.subramanian vIT University VelloreTamil Nadu632014India Faculty of School of Electrical Engineering VIT UniversityVelloreTamil Nadu632014India

Induction motor drives(IMDs)can achieve high performance levels comparable to dc motor drives.A major problem in getting high dynamic performance in an IMD is the coupling between theflux and torque producing components of stator *** is successfully overcome in FOC(Field-Oriented Control)IM,making it to the industry standard *** performance of an IMD with an improved power quality converter at the front end is presented in this *** the IMD,boost converter is employed to reduce power quality difficulties at the utility *** the boost converter contains only one switch,it results in a low processing time and *** ensure sinusoidal supply currents with high PF(Power Factor)and minimal THD(Total Harmonic Distortion),a novel PFC(Power Factor Corrector)control technique is *** enhance the performance of the converter and to lower distortions at the motor side,PI(Proportional Integral)controller is incorporated at the PFC *** it controls the DC bus *** proposed boost converter improves power quality by lowering overall harmonic distortion of AC mains current,improving power factor correction,and regulating dc-link *** is designed,modelled,and simulated in the MATLAB/simulink *** a DSP(Digital Signal Processor),the suggested system’s performance is experimentally *** system’s performance is evaluated for speed and load torque,and the power quality indices are determined to meet IEEE-519 standards under all operating *** the obtained results,it is evident that the proposed system mitigates the power quality issues effectively.

关键词： Induction motor PI controller boost converter power factor corrector

Experimental Investigation for NO_x Emission reduction in Hydrogen Fueled Spark Ignition Engine Using Spark Timing retardation, Exhaust Gas recirculation and Water Injection Techniques

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Thermal Science 2019年第4期28卷 789-800页

作者： JEErAGAL ramesh k.A.subramanian Engines and Unconventional Fuels Laboratory Centre for Energy Studies IIT Delhi

The experimental tests were carried out on a single cylinder hydrogen fueled spark ignition(SI)generator set with different spark timings(4-20℃A bTDC),exhaust gas recirculation(EGr)up to 28% by volume and water injection up to 1.95 kg/h(maximum water to fuel mass ratio of 8:1).The engine speed was kept constant of 3000 r/*** NOx emission and thermal efficiency of engine with gasoline and hydrogen fuel operation at 1.4 kW power output are 5 g/kWh and 12.1 g/kWh,and 15% and 20.9% *** order to reduce the NOx emission at source level,retarding spark timing,exhaust gas recirculation(EGr),and water injection techniques were *** emission decreased with spark timing retardation,EGr,and water *** emission with hydrogen at 1.4 kW power output decreased from 12.1 g/kWh with maximum brake torque(MBT)spark timing(10℃A bTDC)to 8.1 g/kWh with retarded spark timing(4℃A bTDC)due to decrease in the in-cylinder peak pressure and *** Nox emission decreased to 6.1 g/kWh with 20% EGr due to thermal and chemical dilution ***,thermal efficiency decreased about 33% and 17% with spark timing retardation and 20EGr respectively as compared to that of MBT spark ***,in the case of water injection,the NOx emission decreased significantly without affecting the thermal efficiency of the engine and it is 5.6 g/kWh with water-hydrogen ratio of 4:1(water flow rate of 0.92 kg/h).Water injection is the best suitable method to reduce the NOx emission in a hydrogen fueled engine compared with the spark timing retardation and EGr technique.

关键词： hydrogen spark ignition engine spark timing exhaust gas recirculation NOx emission water injection

Characteristics of Energy Fluxes and Cold Frontal Effects on Energy Exchange over a Boreal Lake

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2025年第02期 357-372页

作者： Lujun XU Huizhi LIU Ivan MAMMArELLA Aki v?H? Joonatan ALA-k?NNI Xuefei LI Qun DU Yang LIU Timo vESALA State key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Department of Atmospheric Sciences Yunnan University Institute for Atmospheric and Earth System research/Physics Faculty of ScienceUniversity of Helsinki

Understanding the characteristics and variations of heat exchange and evaporation of lakes is important for regional water resource management and sustainable development. Based on eddy covariance measurements over Lake vanajavesi in southern Finland, characteristics of energy fluxes and cold frontal effects on energy exchange were investigated. The lake acted as a heat sink in spring and summer and a heat source in winter. The latent heat flux reached its minimum value in the morning and peaked in the afternoon. The diurnal variation of sensible heat flux was opposite to that of latent heat flux. Impact factors for the sensible heat flux were mainly the lake-air temperature difference and the product of lake-air temperature difference and wind speed. The latent heat flux was mainly affected by the vapor pressure deficit and the product of vapor pressure deficit and wind speed. The annual mean values of bulk transfer coefficients for momentum, heat,and water vapor were 1.98 × 10–3, 1.62 × 10–3, and 1.31 × 10–3, respectively. Bulk transfer coefficients for heat and water vapor were not equal, indicating that the parameterization of energy exchange in numerical models, where the assumption that the heat coefficient equals the water vapor coefficient needs improvement. During the ice-free season, cold fronts resulted in 28 sensible heat pulses and 17 latent heat pulses, contributing to 50.59% and 34.89% of sensible and latent heat exchange in Lake vanajavesi. These results indicate that cold fronts significantly impact the surface energy budget and evaporation over lakes.

关键词：

Effect of Processing Parameters on Crystal Orientation of Microstructure in High Niobium-Bearing Microalloyed Steel

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel research International 2011年第S1期18卷 466-470页

作者： subramanian S v McMaster University HamiltonOntarioCanada

The present studies are aimed at understanding the effect of cooling rate and prior strain on the evolution of morphology,orientation relationship (Or) and variant selection in pipeline steel with 0.09wt% *** identical prior austenite grain,all products include granular bainite(GB) by coherent transformation,keep orientation relationship (Or) with parent *** cooling and large deformation below T nr both can raise drive force of coherent transformation and weaken variants selection,and it can generate higher frequency of high angle boundaries (HABs) (≥15degree).Moreover,large deformation by few passes below T nr can accelerate nucleation of ferrite grains at the austenite boundary by incoherent *** fine grains haven’t Or with prior austenite grain in any side of boundary,and exhibit significant misorientations between themselves.

关键词： orientation relationship EBSD low carbon bainite microalloyed steel ferrite grain

recrystallization Behavior Design for Controlling Grain Size in Strip rolling Process

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel research International 2008年第1期15卷 39-44页

作者： ZHU Guo-hui S v subramanian School of Materials Science and Engineering Anhui University of Technology Ma＇anshan 243002 Anhui China Department of Materials Science and Engineering McMaster University Hamilton LSS 4A7 Ontario Canada

To promote effectively dynamic recrystallization and obtain a homogeneous distribution of ultrafine grain size in strip finish rolling process,the behavior of static and dynamic recrystallization must be appropriately designed to provide an ultrafine austenite microstructure without mixed grain *** design of rolling schedule was analyzed based on the control of the recrystallization behavior to achieve ultrafine grain size in the strip rolling process of niobium microalloyed *** experimental simulations were presented to validate the twice dynamic recrystallization design to achieve ultrafine grain size control.

关键词： twice dynamic recrystallization critical strain dynamic recrystallization ultrafine grain size

Laser interaction with undercritical foams of different spatial structures

在线全文

学校读者我要写书评

暂无评论

Matter and radiation at Extremes 2025年第1期10卷 39-47页

作者： J.Limpouch v.Tikhonchuk O.renner Sh.Agarwal T.Burian J.Cervenka J.Dostál r.Dudzák D.Ettel A.Gintrand L.Hudec L.Juha O.klimo M.krupka M.krus T.Lastovicka r.Liska W.Nazarov S.k.Singh M.Šilhavík S.Weber Faculty of Nuclear Science and Physical Engineering Czech Technical University in Prague11519 PragueCzech Republic The Extreme Light Infrastructure ErIC ELI-Beamlines FacilityZa Radnicí83525241 DolníBrezanyCzech Republic Centre Lasers Intenses et Applications University of Bordeaux-CNRS-CEA351 Cours de la Liberation33405 TalenceFrance Institute of Physics Czech Academy of SciencesNa Slovance 1999/218200 PragueCzech Republic Institute of Plasma Physics Czech Academy of Sciences18200 PragueCzech Republic Faculty of Mathematics and Physics Charles University12116 PragueCzech Republic Faculty of Mechatronics Informatics and Interdisciplinary StudiesTechnical University of Liberec46117 LiberecCzech Republic Independent Foam Target Supplier St.AndrewsFifeScotland

The interaction of high-power laser pulses with undercritical foams produced by different techniques but with the same average density is studied at the PALS laser *** spatial-temporal evolution of X-ray emission is observed using an X-ray streak camera,electron and ion temperatures are measured by X-ray spectroscopy,and hot-electron production is characterized by monochromatic X-ray *** of a femtosecond laser probe pulse through foams is observed in the near and far *** spite of large differences in pore size and foam structure,the velocity of ionization front propagation is quite similar for all the foams studied and is slower than that in a homogeneous material of the same average *** ion temperature in the plasma behind the ionization front is a few times higher than the electron ***-electron production in plastic foams with small pores is strongly suppressed compared with that in solid targets,whereas in foams produced by additive manufacturing,it is significantly increased to the level observed in bare copper foil targets.

关键词： temperature. interaction critical